The JQuery Validation plugin is normally bundled with a file named additional-methods.js that adds some more validation methods to the basic ones that are in the plugin.
Two of which, 'accept' (for validating mime-types on input[type=file]) and 'extension' for validating file extensions (again, on input[type=file]), have support within MVC in the form of validation attributes (FileExtensionsAttribute and AcceptAttribute)
Currently the templates provided does not include that additional file, hence out-of-the-box these validation attributes only apply on server-side.
A fix would be to either add the nuget-package for the additional methods into the template, or to update the JQuery.validation nuget package to always include the additional methods file.
The default Bundle for jquaeyval should be updated as well.
Two of which, 'accept' (for validating mime-types on input[type=file]) and 'extension' for validating file extensions (again, on input[type=file]), have support within MVC in the form of validation attributes (FileExtensionsAttribute and AcceptAttribute)
Currently the templates provided does not include that additional file, hence out-of-the-box these validation attributes only apply on server-side.
A fix would be to either add the nuget-package for the additional methods into the template, or to update the JQuery.validation nuget package to always include the additional methods file.
The default Bundle for jquaeyval should be updated as well.